In the case of computer tomographs in particular, it is necessary to support a drum-shaped body relative to the housing such that it can be turned around an axis of rotation for purposes of preparation of tomographic images. To irradiate a patient who is to be examined, an x-ray tube is placed in the drum-shaped body and on the side of the drum diametrically opposite the x-ray tube, radiation detectors which receive the emitted x-radiation are provided.
A bearing arrangement described in the context of an electrical machine is disclosed in DE-OS 15 75 635. Here the outer ring of the bearing is connected to the housing or the frame by way of a damping element or by way of several damping elements which are arranged in a uniformly distributed manner over the periphery of the outer bearing ring. The inner ring of the bearing carries the turning component.
Other publications such as DD-PS 78 523, DE 25 55 021 C2 and DE 30 32 820 C2 disclose bearings for diverse applications in which elastomer blocks or sleeves consisting of elastomer material are used to impart an improved damping property to the bearing.
A roller bearing for a nuclear spin tomograph with magnetic roll bodies and with an inner ring and outer ring between which the roll bodies can roll is described in WO 02/27203 A1. This document describes that the outer ring is surrounded by a nonmagnetic ring.
For computer tomographic systems, bearing arrangements are known in which wire bearings with inserted damping elements are used. Therefore the rotary drum is supported there by way of a ball bearing with traverse wires, the traverse wires being placed in damping plastic inserts. In addition, ceramic balls are used as the roll bodies for the bearing.
It has been found that existing bearing systems especially in computer tomographs still do not meet necessary of desired requirements because the bearing arrangement in operation (when the drum is turning) has relatively high noise development. It is thus hardly possible to meet the requirement for a quiet bearing which produces at most 55 dB(A). The damping of the bearing arrangement therefore has been inadequate for a long time.
Another problem also linked to noise development is that the rotating drum in operation has a not inconsiderable ovalness. That is, the bearing has not been able to grip and support the drum such that it retains a largely round shape.